- Factories, in general, are associated with manufacturing products, and many times that requires using many different materials in the creative process. As chemicals, heat and waste from the new products go through assembly, they all need to be removed from the factory. Open air vents, smokestacks and chimneys release the pollution from the factory into the air.
- While it may seem like there is an endless supply of air around the earth, there are also billions of factories around the world releasing pollution. So, the one, little, black cloud you see over one factory is repeated endlessly all over the world. As long as the factories are working, pollution is being created.
- Large cities, such as Los Angeles, have a layer of smog, which is polluted air over the whole city. If air pollution continues as it has been, before too long, the entire earth will have an additional ring around it consisting of polluted air from factories, cars, and people.
